if i save a game in savestate 1, start another game and save it in savestate 1 aswell, will it override it?

and how can i manually save a savestate in a custom folder, like i can in the pcsx for the ps 1?

like for instance, i want to save a savestate from final fantasy right before omegae weapon, so i want to save the savestate under the name omega in my final fantasy folder among other savestates from many different parts of the game?

Config->Plugin/BIOS selector->"Folders" tab and you can change folder for savestates, but you cannot "save as" and type in a name, nor you cannot load a savestate with different name than default - at least currently. Savestates name comes from game code and choosen slot and that also means an answer to your first question - no they aren't shared among different games.